1. Field of the Invention
This invention relates to an apparatus for forming hollow-core concrete slabs with a brick, block, stone or other embossed imprint on a surface.
2. Description of the Related Art
U.S. Pat. No. 4,369,153 which issued Jan. 18, 1983 to Nash et al discloses a machine which casts hollow core concrete panels in a single casting operation utilizing a slip form technique to fill cores with core material which can be dumped from the core after curing of the concrete has been accomplished. U.S. Pat. No. 4,369,153 is incorporated herein by reference.
In single casting operations, hollow core concrete panels are formed on a moving bed in which concrete is first poured around the front end of a slip form which forms the bottom layer of the concrete panel. The bed moving past the slip form shapes the bottom layer of the concrete panel. As the concrete travels on the bed past the slip form, core material which may be an aggregate, is fed into openings in the slip form to fill the desired cores with core material.
Such casting uses relatively wet concrete and often involves beds of 600 feet or more in length. A variety of patterns may be placed into the still wet concrete before it has cured. Many hand laid patterns may be made with the involvement of skilled laborers. However, such hand-operated techniques are difficult to control, since one mistake may ruin a long length of finished plank.
A number of surface finishes have been formed in which longitudinal ribbing is placed into the screed surface. This is relatively easy to accomplish as typified by U.S. Pat. No. 4,457,682. Alternatively, the top concrete may be carefully washed to expose the underlying aggregate rock. See U.S. Pat. No. 4,360,333.
Other means for making a simulated brick wall involve the placement of thin bricks into the still wet concrete. British patent 1,539,179 is an example.
The art described in this section is not intended to constitute an admission that any patent, publication or other information referred to herein is "prior art" with respect to this invention, unless specifically designated as such. In addition, this section should not be construed to mean that a search has been made or that no other pertinent information as defined in 37 C.F.R. .sctn. 1.56(a) exists.